Mechanism for cutting a moving web of sheet material

ABSTRACT

A mechanism for cutting a moving web of sheet material to form a plurality of separate sheets of material, the mechanism comprising a pair of relatively movable blades disposed between a pair of driven rollers around which the web of material is passed, a movable carriage having a freely rotatable guide roller around which the web passes before passing around the first of said driven rollers, means for moving said carriage so as temporarily to arrest movement of the web between the driven rollers by forming a loop in the material and means synchronized with said carriage moving means for actuating the blades to cut the material whilst the web is arrested as aforesaid, there being also provided in association with each driven roller suction means for holding material on to the peripheries thereof.

United States Patent [56] References Cited UNITED STATES PATENTS 4/1963 Fischeretal.

[72] Inventors Reginald Leonard Ballard 6/1965 Scott et al....

2/1954 Dutro...,..... 12/1964 Pechmann....i...............

[22] Filed June7, 1968 Patented Jan.5,l97l- Primary Examiner Andrew R. Juhasz Assistant Examiner- Leon Gilden [73] Assignee Phillips Engineering Limited Birmingham, England June 9, 1967 [32] Priority Attorney-Holman, Glascock, Downing and Seebold [33] Great Britain ABSTRACT: A mechanism for cutting a moving web of sheet material to form a plurality of separate sheets of material, the mechanism comprising a pair of relatively movable blades disposed between a pair of driven rollers around which the web of material is passed, a movable carriage having a freely [54] MECHANISM FOR CUTTINGAMOVING WEB 0F rotatable guide roller around which the web passes before SHEET MATERIAL passing around the first of said driven rollers, means for mo,v-

ing said carriage so as temporarily to arrest movement of the web between the driven rollers by forming a 'loop in the material and means synchronized with said carriage moving means for actuating the blades to cut the material whilst the web is arrested as aforesaid, there being also provided in as- [51] Int. 826d 5/16,

sociation with each driven roller suction means for holding material on to the peripheries thereof.

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MECHANISM FOR CUTTING A MOVING WEB OF SHEET MATERIAL This invention relates to mechanism for cutting a moving web of sheet material at intervals and in directions transverse to the length ofthe web in order to form a plurality of separate sheets of material, the object of the invention being to provide such a mechanism in an improved form.

Mechanism in accordance with the invention comprises a pair of relatively movable blades, a first driven roller and a second driven roller disposed respectively on opposite sides of said blades, a movable carriage having a freely rotatable guide roller around which in use the web of sheet material is passed before being passed around said first driven roller, suction means associated with each of said driven rollers for holding sheet material on to the peripheries thereof, and means for actuating said blades to cut the web of sheet material, said means being actuable in synchronism with the movement of said carriage so that cutting is effected at a time when the web of material passing from said first driven roller to the second driven roller and between said blades is temporarily arrested by reason of the carriage moving in a direction which will cause a loop to be formed in the material before it reaches the first driven roller, the drive between the first driven roller and the web of material and/or the drive between the first driven roller and driving means to which it is connected being such as to permit slip between the roller and the web whilst the latter is temporarily arrested as aforesaid.

Conveniently, said carriage is mounted for reciprocable linear motion and is driven by means of a crank having an adjustable throw. The suction means associated with each of said driven rollers may comprise a stationary pipe or chamber to which suction is applied and which communicates with grooves or slots formed in the periphery of the roller so as to form a vacuum therein when said grooves of slots are covered by the web or sheets ofcut material.

The invention will now be more particularly described with reference to the accompanying drawing wherein FIG. 1 is a sectional elevation showing one example of a mechanism in accordance with the invention;

FIG. 2 is a section on line 2-2 of FIG. 1 showing a detail of the mechanism; and

FIG. 3 is a section on line 3-3 of FIG. 1 showing another detail of the mechanism.

Referring to the mechanism shown in the drawing, there is provided a pair of relatively movable blades which conveniently comprises a fixed blade and a movable blade 11. On opposite sides of said blades are mounted respectively a first driven roller 12 and a second driven roller 13. The first driven roller 12 is connected by means of a conventional friction clutch to driving means (not shown) which when the clutch is not slipping will drive said roller at a speed such that its periphery is moving twice as fast as the speed of a web of material 14 which in use will be advanced towards said first driven roller by means of any suitable form of feed rolls (not shown), it being understood that said web of material which may be of paper or any other material can have matter printed upon it or be subject to any other like operation as may be desired. The second driven roller 13 is driven at a speed which is slightly greater than twice the web speed.

There is also provided a movable carriage 15 which is conveniently mounted on a guide 16 for reciprocable rectilinear motion, one end of said carriage being connected to a crank 17 of variable throw. The opposite end of said carriage carries a freely rotatable guide roller 18 and the arrangement is such that said carriage can move in a direction parallel to a plane containing the axes of said driven rollers. Conveniently said carriage is disposed beneath the driven rollers 12 and 13 and beneath the carriage there is provided a further freely rotatable roller 19 around which the web of material is led before being passed round said freely rotatable roller 18 on the carriage and thence round the first driven roller 12, between the relatively movable blades 10 and 11 and thence on to the second driven roller 13.

In use, the aforesaid carriage 15 will be reciprocated and it will be appreciated that in one direction of motion (i.e. when moving to the right as shown in FIG. 1) it will be adapted to form a loop of material between the first driven roller 12 and said further roller 19 beneath the carriage. The drive between the periphery of the first driven roller 12 and the web of material and/or the drive between said roller and the friction clutch permits slip to occur between the periphery of the first driven roller and the web whilst said loop is being formed and at this moment it will be appreciated that the web of material in front of the first driven roller 12 will be temporarily arrested. It is then possible to make, a cut in the web which is accurately positioned and to this end the movable blade 11 is connected to a pivoted lever 20 which is actuated by cam means 21 rotated by a gear wheel 22 which meshes with another gear wheel 23 which drives the aforesaid crank 17. Operation of the blades 10 and 11 to cut the web 14 will therefore be synchronized with movement of the carriage to ensure that cutting only takes place when the web of material in front of the first driven roller 12 is temporarily stopped.

It is however necessary to ensure that after a cut has been made the then leading end of the web of material is passed on to the second driven roller 13 in order to control the movement of the material and to this end suction means are associated with each driven roller for holding the material on to the periphery of each roller. in the case of the first driven roller 12 there is provided a chamber 24 which partially em braces the exterior of the roller on that side thereof nearer to said blades, the roller being formed with a plurality of axially spaced circumferentially extending grooves 25 which communicate with the interior of said chamber and to which suction will be applied. Thus then the web of material is passed round said first roller the grooves 25 will be covered by the web and a vacuum will be formed in the grooves so that the web will be held on to the periphery of the roller, it being understood however that a slip can occur between the roller and the web when necessary as above described. A plurality of stripper fingers 26 are provided which extend into said grooves for stripping the web from the roller 12 and directing it towards the blades 10 and 11. In the case of the second driven roller 13 a pipe 27 connected to a source of suction is inserted into the interior of the roller which is hollow and said pipe communicates with a chamber 28 which engages the inner periphery of the roller over a small arc thereof. The roller itself is formed with a plurality of circumferentially spaced axially extending slots or rows of holes 29 which communicate with said chamber 28 when aligned therewith so that a vacuum will be formed beneath the cut sheets of material over a small are adjacent to the upper part of the roller. The sheets of material will there fore be carried part way round the second roller before meeting any convenient form of stationary stripping means 30 which will strip the sheets from the roller and enable them to fall into any conveniently positioned receptacle (not shown).

It will be appreciated that the throw of the aforesaid crank can be adjusted and the moment of actuation of said blades can also be adjusted to vary the intervals between successive actuations of the blades in order to vary the length of sheets that are cut, whilst the fact that the web is temporarily arrested whilst cutting is being effected will enable the cuts to be made with great accuracy.

We claim:

1. Mechanism for cutting a moving web of sheet material at intervals and in directions transverse to the length of the web in order to form a plurality of separate sheets of material, said mechanism comprising a pair of relatively movable blades, means for advancing said web towards the blades at a predetermined speed, a first driven roller and means for driving said first driven roller at a peripheral speed greater than said predetermined speed, a second driven roller, said first and second rollers being disposed respectively on opposite sides of said blades, a carriage having a freely rotatable guide roller around which in use the web of sheet material is passed before being passed around said first driven roller, means for reciprocating said carriage, suction "means associated with each of saiddriven rollers for holding sheet'material on to the vperipheries thereof, and means for actuating said blades to cut 'betweensaid web'of material and said means for driving said first driven roller.

2." Mechanism as claimedin claim 1 wherein the suction means associatedwith said first'driven' roller comprises a suction chamber disposed externally of the roller and in engagement-therewith, said roller being formed on its exterior with a plurality. of axially spaced circumferentially extending grooves.

3.'Mechanism as claimed in claim 1 wherein the suction means associated with said second driven roller comprises'a suction chamber arranged inside the roller so as to extend over a smallarc of the inner periphery thereof, said roller being'formed-with a plurality of circumferentially spaced apertures which are arranged to communicate with said suction chamber when aligned therewith whereby suction will be applied to the exterior of the roller over a small arc thereof 

1. Mechanism for cutting a moving web of sheet material at intervals and in directions transverse to the length of the web in order to form a plurality of separate sheets of material, said mechanism comprising a pair of relatively movable blades, means for advancing said web towards the blades at a predetermined speed, a first driven roller and means for driving said first driven roller at a peripheral speed greater than said predetermined speed, a second driven roller, said first and second rollers being disposed respectively on opposite sides of said blades, a carriage having a freely rotatable guide roller around which in use the web of sheet material is passed before being passed around said first driven roller, means for reciprocating said carriage, suction means associated with each of said driven rollers for holding sheet material on to the peripheries thereof, and means for actuating said blades to cut the web of sheet material, said blade actuating means including a cam rotatable in synchronism with reciprocation of said carriage whereby the blades are operative to cut the web of material when the carriage has formed a loop in said web so as temporarily to arrest the web between the first and second driven rollers, means being also provided to permit slip between said web of material and said means for driving said first driven roller.
 2. Mechanism as claimed in claim 1 wherein the suction means associated with said first driven roller comprises a suction chamber disposed externally of the roller and in engagement therewith, said roller being formed on its exterior with a plurality of axially spaced circumferentially extending grooves.
 3. Mechanism as claimed in claim 1 wherein the suction means associated with said second driven roller comprises a suction chamber arranged inside the roller so as to extend over a small arc of the inner periphery thereof, said roller being formed with a plurality of circumferentially spaced apertures which are arranged to communicate with said suction chamber when aligned therewith whereby suction will be applied to the exterior of the roller over a small arc thereof. 